The colouration or highlighting of selected strands of hair has been practised for many years and numerous methods for achieving the desired effect have been published in the patent and trade literature. Generally, there are three methods for highlighting hair, known in the trade as "capping", "combing" and "foiling". In capping, the subject's hair is covered with a thin rubber cap having a multiplicity of small holes therethrough. A hooking device is then used to pull selected strands of hair through the cap and colour or bleach is then applied to the hair strands. This procedure has numerous disadvantages because the operator cannot see the hair to be selected through the rubber cap, and cannot accurately select the optimum number of hairs to be treated. It can also be extremely painful if the steel hook is inadvertently jabbed into the scalp. It is also difficult to pick all of the hair up at the root with the result that some is selected at midshaft resulting in unsatisfactory overall colouring. It is difficult to apply the colour close to the hair roots and it is also difficult to apply more than one colour. It is also difficult to remove the cap from the head after treatment and often requires a tedious cutting procedure. Attention is directed to U.S. Pat. No. 4,165,754 issued Aug. 28, 1979 and U.S. Pat. No. 4,155,369 issued May 22, 1979, as examples of the cap method.
The combing method involves a comb, which is dipped into the treating liquid, and then pulled through the hair to be treated. Only relatively large swatches of hair can be treated in this manner and it is difficult to avoid bleeding of the treating liquid to those parts of the head that are not to be treated.
The foil method, which is widely used in the salon market, requires the operator to select the appropriate number of swatches and to wrap each swatch in a flexible, chemically impervious foil generally, but not essentially, an aluminum foil so as to form a packet around the swatch. Once the foil is in place the treating solution is introduced into the packet and the ends thereof are crimped so as to retain the solution in close contact with the hair. As it is usual to treat some fifty to seventy swatches in this manner, it takes considerable manual dexterity on the part of the stylist and more than 45 minutes to completely prepare a head of hair. As the treatment solutions usually require from 10 to about 45 minutes to be effective, this causes considerable problems. It will be appreciated that the first hair to be treated will be completely finished before the last hair to be treated has been processed at all. Stylists try to compensate for this by using different strength solutions as the wrapping process continues or by applying heat to the later treated hair to speed up the process. The result is frequently uneven colouring over the head if not actual damage to the hair. Because of the high degree of skill required to produce satisfactory results, the foiling method is not suitable for home use. Several attempts to improve upon the basic foiling method have been described in the literature and attention is directed to U.S. Pat. Nos. 5,042,514; 2,819,721 and 2,655,924 which all describe methods and apparatus for colouring selected swatches of hair using prefabricated sleeves or tubes into which the hair is drawn for treatment using a transverse hook or jaws to grip and guide the hair. The treating solution is then poured into the tube which is then clamped shut for the appropriate treating time. While an improvement over previous methods in that more hair can be treated more quickly, the tubes are difficult to handle and it is difficult to control how much hair is drawn into the tube and the hair is frequently grasped in midshaft, making it difficult to treat the roots and sometimes impossible to draw the entire swatch into the tube, especially if the hair is rather long. Because the hair is actually gripped by the jaws, adjustments are not readily made without painful pulling of the hair. There is, therefore a need for an improved method and apparatus for highlighting hair that is suitable for both home and salon use which can be used on very small swatches of hair, which can treat hair very close to the roots and which can be used to retouch previously treated hair.